直流频变电缆参数测量与故障定位原理

摘要

The research on frequency-dependent parameters has always been one of the keys to solving cable problems. In this paper,a parameter measurement method is proposed,which can be used in actual projects.By measuring the open-circuit and short-circuit impedances in the corresponding sequences at different frequencies,the distribution of parameters in frequency domain are calculated,and the accurate cable parameters that vary with frequency are ob?tained.Accordingly,a fault location method for VSC-HVDC cables is proposed by combining wavelet transform meth?od,which is suitable for the frequency-dependent parameter model.By using this model,the locations can be calculat?ed using double terminal voltage and current from both ends respectively.The proposed method changes the traditional idea that wavelet transform can only be used to identify the travelling wave head,and by applying the wavelet transform to the fault location based on the calculation of impedances,it can improve the location precision effectively.%对于频变参数的研究一直是解决电缆问题的关键.首先提出了可以应用于实际工程中的电缆参数测量计算方法,在不同频率下通过测量线路对应模量的开路阻抗和短路阻抗,计算对应模量的频域分布参数,得到随频率变化的精确电缆参数;根据计算参数,提出了一种结合小波算法的应用于VSC-HVDC直流系统线路的故障定位方法,该方法适用频变参数模型利用双端电压、电流分别从两端计算沿线电压分布计算故障处位置.突破了小波变换仅利用于行波波头识别的传统观念,将小波变换用于频变电缆的阻抗法故障定位计算中切实可行,并且提高了定位精度.